Intermediate stop device for pneumatic elevators.



G. F. STEBDMAN.

INTERMEDIATE STOP DEVICE FOR PNEUMATIC ELEVATORS.

APPLICATION FILED NOV. 22, 1912.

1 1 O 1 1 O2, Patented June 23, 1914.

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GEORGE F. STEEDMA'N, OF ST. LOUIS, MISSOURI.

INTERMDIATE STOP DEVICE FOR PNEUMATIC ELEVATORS.

To all whom it may concern Be it known that I, GEORGE F. STEEDMAN, a citizen of the United States, residing at St. Louis, Missouri, have invented a certain new and useful Improvement in Intermediate Stop Devices for Pneumatic Elevators, of which the following is a full, clear, and exact description, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention relates to pneumatic elevators of the type in which an air hoist is connected directly by its piston rod to the elevator cage, or is connected to the cage by means of a rope or other flexible member. In an elevator of this class, it is usual that the elevator cage travel between two fixed limits and make no intermediate stop at which a load or a portion of a load is received or discharged. This fact is because of theelasticity of the actuating pressure which would cause the elevator cage tofall or rise if its load were increased or diminished at an intermediate point.

The object of my invention is to provide an attachment for elevator cages which is so constructed that it will be safe and practicable to stop the cage at a point intermediate its upper and lower levels so'that the load on the cage can be received or discharged at the intermediate stop.

Figure 1 of the drawings is a side elevational view of a compressed air elevator constructed in accordance with my invention; Fig. 2 is an enlarged sectional view taken on approximately the line 2-2 of Fig. 1, looking in'the direction indicated by the arrow; and Fig. 3 is a. similar view showing the manually operated locking means on the cage in operative position.

Referring to the drawings which illustrate the preferred form of my invention, A designates the cage of a pneumatic elevator, said cage being arranged to travel vertically between two levels designated, respectively, as a lower level and a higher level, and B designates a cylinder provided with a piston that operates the cage A in a well-known manner. The piston rod 1 of said cylinder B is provided at its upper end with a sheave .2 that cooperates with a' rope or cable 3 which leads downwardly from a stationary bracket on the supporting framework under the sheave 2, thence Specification of Letters Patent.

Application filed November 22, 1912.

Serial No. 2'32,864-.

upwardly over sheaves 4 on said framework and downwardly to the cross-beam 5 on the cage A. A valve 1s provided for governing Patented June 23, 1914.

the supply of compressed air to and from the cylinder B by means of the pipes 6 and 7 so as to control the movement of the cage A. Then said valve is in one of its extreme positions, the connections are so made that the cylinder will lift the cage and when in its other extreme position will permit the cage to descend.

Means are provided for positively locking the cage A. intermediate the two levels between which it travels, and in the preferred form of my invention as herein shown, said means consists of dogs, plungers or bolts 9 on the cage A that cooperates with notches 10 and 11 in the vertically disposed guides at on which the cage travels, the notches 10 and 11 being located at any convenient positions intermediate the upper and lower levels. Any suitable type of mechanism can be used for actuating and controlling the mechanical locking devices 9 on the cage,

and in the form of my invention herein shown said governing mechanism consists of a lever 12 connected to a vertlcally dis- 7 posed shaft 18 on the cage that is provided with an arm 14 that is fastened by means of a connecting device 15 to a lever 16 arranged on the under side of the platform of the cage between the locking devices 9. Each of said locking devices is joined by means of a connecting device 17 to one end of the lever 16, and coiled springs 18 are provided for moving the locking devices 9 outwardly or into engagement with the notches in the guides with which they cooperate. The catch 19 on the cage A cooperates with the manually-controlled lever 12 to normally hold the locking devices 9 in an inoperative position, as shown in Fig. 2, but when the lever 12 is disengaged from said catch the springs 18 force the locking devices 9 outwardly so that they will spring into the noches 10 or 11 in the cage guides a when they come into alinement with said notches.

It will be noted that the locking devices 9, and their cooperating notches 11 are beveled on their upper surfaces and are so designed that the notches and locking device are inoperative when the cage moves upwardly, but are operative as the cage moves downwardly. In order to eliminate the pes controlling valve is provided with an actuating device D to which operating chains or cables 20 are connected, and said device D is provided with an arm 21 to which a C-link 22 is pivotally connected at a point slightly off center or to one side of the center of rotation of said valve, the upper end of the C-link 22 being connected to a contractile spring 23. In case the operator fails to manually move the fluid-controlling valve far enough to bring it to either of its extreme positions, the spring 23 will act to complete the movement of the valve; or, in other words, throw the valve over center owing to the fact that said spring is eccentrically connected to the valve-operating device D, making it impossible to accidentally keep the valve on center.

To cause the cage A to move upwardly the operator turns the valve-operating-device D into the position shown in full lines in Fig. 1 so as to cause the pressure to be properly admitted and exhausted to and from the cylinder. If it is desired to stop the cage in the position shown in broken lines in Fig. l, the operator releases the lever 12 on the cage so as to cause the locking devices 9 to become operative, and he also turns the valve-operating device D into the position shown in broken lines in Fig. 1 when the cage reaches a point a trifle above the position where it is desired to stop the cage, thereby causing the cage to move downwardly until the locking devices 9 spring into the notches 10 in the stationary guides a on which the cage travels. The load on the cage can now either be diminished or increased without affecting the position of the cage for the devices 9 on the cage mechanically support the cage and the valve is in its lowering position. When the operator desires to ascend from the position in which he stopped the cage, he first actuates the valve-operating device D so as to cause the cage to ascend, and thereafter moves the manually-controlled lever 12 on the cage into engagement with the catch 19 that holds the locking devices 9 in an inoperative position. If the operator desires to stop the cage in the position shown in broken lines in Fig. 1 when the cage is descending he merely releases the lever 12 after the cage has passed the notches 11, and when the locking devices come into which the cage travels.

alinement with the notches 10 they will spring into same and thus securely lock the cage. To descend from this position to the lower level the operator first has to shift the valve-operating device D into the position shown in full lines in Fig. 1 so as to cause the cage to ascend slightly in order to permit the hook-shaped locking devices 9 to be withdrawn from engagement with their cooperating notches 10, and after said locking devices 9 have been locked in an inoperative position, by means of the lever 12 and catch 19, the operator shifts the valve-operating device D back into its former position, shown in broken lines in Fig. 1, so as to cause the cage to move downwardly.

From the foregoing it will be seen that in a pneumatic elevator of the construction above described any variation in the weight of the load on the cage when the cage is stopped at certain points intermediate the levels between which it travels, has no eiiect on the cage and will not cause the cage to move either upwardly or downwardly. Gonsequently, such a hoist can be used successfully for loading or unloading a wagon or other object having a supporting platform that lies in a different horizontal plane than the upper and lower levels between Another desirable feature of such a hoist is that there is no possibility of the cage-locking devices becoming inoperative accidentally and thus releasing the cage.

Another desirable feature of such a hoist is that there is no possibility of the operator carelessly releasing the locking devices and thus permitting the cage to drop suddenly in case a heavy load has been placed on same when the cage was stopped in an intermediate position, owing to the fact that the valve-operating device D has to be turned into such a position before the mechanical locking devices are released that the pressure on the piston is suiiicient to sustain the load and cause the cage to move upwardly far enough to permit the hook-shaped locking devices to be withdrawn from engagement with their cooperating notches. And still another desirable feature of my invention is that by providing the spring-actuated device preventing the valve froin accidentally stopping at a central position, it is impossible for the operator of the cage carelessly or by ignorance to hold or stop the cage at an intermediate level and then receive or dis charge a load. This spring device insures the operating valve either being at one extremity or the other of its motion.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

In a device of the class described, an elevator cage, guides in which the cage travels, coacting means on the cage and guides, operative only upon descent of the cage, to support the said cage at predetermined elevations, pneumatic hoisting means and a controlling device for maintaining the said hoisting means in either ascending or descending relation, whereby upon actuation of the controlling device to descending relation and the engagement of the cage locking means the hoisting means releases the ten- 10 sion of the hoisting cable.

In testimony whereof I hereunto aflix my signature in the presence of two witnesses, this 16th day of November 1912.

GEORGE F. STEEDMAN.

Witnesses:

R. E. WINKLER, LEON S. BUoKLEs.

Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Patents, Washington, D. O. 

